According to PeterZ's suggestion in https://lkml.org/lkml/2018/9/18/1016,
hard bind retpoline with compiler support and remove minimal stuff.
Tested with both CONFIG_RETPOLINE enabled and disabled.
-v3:
Add Suggested-by[Ingo]
Break build if compiler doesn't support retpoline[Dwmw,Tglx,Ingo]
-v2:
Add compiler support check in Kconfig [Masahiro]
Drop 3rd patch as __insn_is_indirect_jump() may be used in some corner case.[PeterZ]
Zhenzhong Duan (2):
retpolines: Only enable retpoline when compiler support it
retpolines: Remove the minimal stuff of retpoline support
arch/x86/Kconfig | 4 ----
arch/x86/Makefile | 5 +++--
arch/x86/include/asm/nospec-branch.h | 12 ++++++------
arch/x86/kernel/cpu/bugs.c | 13 ++-----------
scripts/Makefile.build | 2 --
5 files changed, 11 insertions(+), 25 deletions(-)
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1.8.3.1